Algorithm changes through the years
Every year, Google changes (read improves) its search algorithm monthly. Changes are normally beta tested in the US before being run out globally. Even then it is sometimes months before the UK catches up. I own a website call http://www.mash4077.co.uk it ranks highly for the search term Mash 4077. which was the old TV series. This website is connected to an old Google Analytics / webmasters account.
We are often bombarded with emails asking questions about why we might have an inappropriate line (finance etc.) or whether or not we are using some new mark up language (or not!). The target shows the ages of the Google engineers that make he decisions. The site will then fluctuate between the first page, then the site might disappear and then it returns. It is just a test bed similar to the ones I use.
Google sometimes rolls out a "major" algorithmic update (such as Google Panda and Google Penguin) that affects SERP results in significant ways. See updates chronologically.
The changes are always subtle until they have been thoroughly tested. They are given names for PR reasons to make Google news worthy.
All of the changes are the same I try and make to our our search algorithm. As I also run bots that crawl the internet many of the improvements Google make I can anticipate as we are trying much the same things.
For example a lot of my current research is based on word structures and sentence formation as a means of optimising content. Google then comes along with "semantic search."
SEOs are in for a rocky ride
Google will try and improve its search metrics. However SEOs are in for a rocky ride. The best Google brains are all involved in Android. Anyone who wants to get ahead in Google is either working on Google mobile or employed to increase mobile advertising revenues. Engineers involved in organic search and algorithmic changes are possible yesterdays news. This has been played out with Amit Singhal, one of Google;s chief veteran search Director resigning in favour of John Giannandrea who is more interested in artificial intelligence? His interest is in machine learning, ie the algorithm will learn through spying on users activity.
The torrent of data thrown off by the world’s internet-connected computers, tablets and phones, and the huge amounts of computing power now available for processing that torrent, means that their algorithms are more and more capable of understanding languages, recognising images and the like. Read more.
Getting computers to think and develop themselves is part of Google's next algorithmic changes. This could mean that if you do not use Google's analytics software you may be left behind.